 class Test1 {
     public static void main(String[] args) {
        A a1 = new A();
        B b1 = new B();
        b1.aa = a1 ;
        b1.aa.a = 2 ;
         System.out.println(a1.a);

     }

}
class  A{
    int a  =1 ;
}
class B{
    A aa ;

}
